controlarm for double track OO level crossing. Fits underneath level crossing, on top of baseboard. Operates all 4 gates , together. Ensure middle pin engages with each gear wheel properly. Moving the control arm will move the gates, and the next pin will lock the gates in other position(open or closed).
Best to test out before fitting level crossing down properly, as movement can be very stiff initially, but the 3D printed nylon plastic gets smooth after a short while.